public function unsubscribe()
 {
     $forumID = $this->urlParams['ID'];
     $memberID = Member::currentUserID();
     if (Member::currentUser() && Forum_Subscribers::already_subscribed($forumID)) {
         $SQL_topicID = Convert::raw2sql($forumID);
         $SQL_memberID = Convert::raw2sql($memberID);
         $query = "DELETE FROM Forum_Subscribers WHERE `ForumID` = '{$SQL_topicID}' AND `MemberID` = '{$SQL_memberID}'";
         DB::query($query);
     }
     return $this->redirectBack();
 }
 public function IsSubscribed()
 {
     $forum_id = $this->owner->ID;
     $member_id = Member::currentUserID();
     return Forum_Subscribers::already_subscribed($forum_id, $member_id);
 }